Metabolites of dietary quercetin: Profile, isolation, identification, and antioxidant capacity

Phytochemical profiling, antiviral activities, molecular docking, and dynamic simulations of selected Ruellia species extracts

The antiviral properties of the flowering aerial extracts of Ruellia tuberosa and Ruellia patula were investigated through phytochemical profiling via LC-MS/MS and HPLC techniques. Qualitative LC-MS/MS analyses identified seventy-seven metabolites from both Ruellia species. R. tuberosa had the highest phenolic content (49.3%), whereas R. patula had the highest flavonoid content (57.8%). Additionally, quantitative HPLC investigations of the compounds identified by LC-MS/MS were performed using the available standard compounds. The main constituents in the R. tuberosa extract was found to be catechin (5321.63 µg/g), gallic acid (2878.71 µg/g), and ellagic acid (2530.79 µg/g), whereas the major compounds in the R. patula extract was found to be rutin (11,074.19 µg/g) and chlorogenic acid (3157.35 µg/g). Furthermore, the antiviral activities of both Ruellia species against HAdV-40, herpes simplex type 2 and H1N1 were evaluated. These findings demonstrated that R. tuberosa was more active than R. patula against all tested viruses, except for the HSV-2 virus, against which R. patula showed greater activity than R. tuberosa, with IC50 values of 20, 65, 22.59, and 13.13 µg/ml for R. tuberosa flowering aerial parts and 32.26, 11.66, and 23.03 µg/ml for R. patula flowering aerial parts, respectively for HAdV-40, herpes simplex type 2, and H1N1. Additionally, computational docking and molecular dynamics simulations were used to assess the molecular interactions between the bioactive compounds and specific viral targets. The combined findings from the in-vitro and in-silico experiments comprehensively evaluated the antiviral activities of both Ruellia species extracts.

Polycommunin A, a dihydrocinnamoyl bibenzyl isolated from the moss Polýtrichum commúne, and its antioxidant activity

A novel polyphenolic compound named Polycommunin A (1) was discovered in the aerial part of the common haircap moss (Polýtrichum commune) widely spread in boreal and temperate climate zones. Aqueous ethanol and extraction of the plant material with further isolation of polyphenolic fraction and preparative HPLC separation allowed obtaining individual compound and identifying it as dimeric dihydrocinnamoyl bibenzyl by NMR spectroscopy and high-resolution tandem mass spectrometry. Polycommunin A demonstrated high in vitro antioxidant activity determined by FRAP and PCL assays and comparable to that of Trolox and Quercetin.

Flavonoids: A treasure house of prospective pharmacological potentials

Flavonoids are organic compounds characterized by a range of phenolic structures, which are abundantly present in various natural sources such as fruits, vegetables, cereals, bark, roots, stems, flowers, tea, and wine. The health advantages of these natural substances are renowned, and initiatives are being taken to extract the flavonoids. Apigenin, galangin, hesperetin, kaempferol, myricetin, naringenin, and quercetin are the seven most common compounds belonging to this class. A thorough analysis of bibliographic records from reliable sources including Google Scholar, Web of Science, PubMed, ScienceDirect, MEDLINE, and others was done to learn more about the biological activities of these flavonoids. These flavonoids appear to have promising anti-diabetic, anti-inflammatory, antibacterial, antioxidant, antiviral, cytotoxic, and lipid-lowering activities, according to evidence from in vitro, in vivo, and clinical research. The review contains recent trends, therapeutical interventions, and futuristic aspects of flavonoids to treat several diseases like diabetes, inflammation, bacterial and viral infections, cancers, and cardiovascular diseases. However, this manuscript should be handy in future drug discovery. Despite these encouraging findings, a notable gap exists in clinical research, hindering a comprehensive understanding of the effects of flavonoids at both high and low concentrations on human health. Future investigations should prioritize exploring bioavailability, given the potential for high inter-individual variation. As a starting point for further study on these flavonoids, this review paper may promote identifying and creating innovative therapeutic uses.

Effect of dietary Achyranthes japonica extract on growth performance of growing pigs and absorption rate of quercetin in blood

This study was done to investigate the effects of the incorporation of Achyranthes japonica extracts (AJE) in diet on the production parameters of growing pigs. Exp 1: Total, 105 crossbred pigs (average body weight: 24.47 ± 2.46 kg) were used in a 6-week feeding trial. Pigs (seven replicates, five pigs per pen) were allotted randomly to three treatments. Dietary treatments: CON (basal diet); basal diet with 0.025% AJE, and basal diet + 0.050% AJE). Growth performance, nutrient digestibility, fecal microbial count, and fecal noxious gas were assessed in this study. Average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F) were not affected by the addition of up to 0.05% AJE. In the case of apparent total tract digestibility (ATTD), dry matter (DM), nitrogen (N), and digestible energy (DE) were not changed in 3rd and 6th weeks of the feeding trial through the addition of AJE up to 0.05% in the growing pig diet. In microbial count, Lactobacillus and Escherichia coli count at 3rd and 6th week was similar in all the treatment diets. The inclusion of AJE at levels up to 0.05% in growing pig diet had no effect on the production of NH3, H2S, acetic acid, and CO2 in the feces. After ending the Exp 1, a total of nine pigs were divided into three treatment groups. Treatment diets were included, TRT1, basal diet + powder quercetin 30 g; TRT2, basal diet + powder quercetin 150 g; TRT3, basal diet + powder quercetin 300g. Rate of absorption in blood was increased with the higher dose of quercetin. The results suggested incorporation of AJE up to 0.05% has no significant effect on ADG, ADFI, and G:F, as well as DM, N, and DE digestibility, fecal microbial count, and fecal noxious gas emission in growing pigs, even though no negative effect was found.

Plant bioactive compounds alleviate photoinduced retinal damage and asthenopia: Mechanisms, synergies, and bioavailability

The retina, an important tissue of the eye, is essential in visual transmission and sustaining adequate eyesight. However, oxidative stress and inflammatory reactions can harm retinal structure and function. Recent studies have demonstrated that exposure to light can induce oxidative stress and inflammatory reactions in retinal cells, thereby facilitating the progression of retinal damage-related diseases and asthenopia. Plant bioactive compounds such as anthocyanin, curcumin, resveratrol, lutein, zeaxanthin, epigallocatechin gallate, and quercetin are effective in alleviating retinal damage and asthenopia. Their strong oxidation resistance and unique chemical structure can prevent the retina from producing reactive oxygen species and regulating eye muscle relaxation, thus alleviating retinal damage and asthenopia. Additionally, the combination of these active ingredients produces a stronger antioxidant effect. Consequently, understanding the mechanism of retinal damage caused by light and the regulation mechanism of bioactive compounds can better protect the retina and reduce asthenopia.

Side Streams of Vegetable Processing and Its Bioactive Compounds Support Microbiota, Intestine Milieu, and Immune System

The industry of vegetable processing generates large amounts of by-products, which often emerge seasonally and are susceptible to microbial degradation. Inadequate management of this biomass results in the loss of valuable compounds that are found in vegetable by-products that can be recovered. Considering the possibility of using waste, scientists are trying to reuse discarded biomass and residues to create a product of higher value than those processed. The by-products from the vegetable industry can provide an added source of fibre, essential oils, proteins, lipids, carbohydrates, and bioactive compounds, such as phenolics. Many of these compounds have bioactive properties, such as antioxidative, antimicrobial, and anti-inflammatory activity, which could be used, especially in the prevention or treatment of lifestyle diseases connected with the intestinal milieu, including dysbiosis and immune-mediated diseases resulting in inflammation. This review summarises the key aspects of the health-promoting value of by-products and their bioactive compounds derived from fresh or processed biomass and extracts. In this paper, the relevance of side streams as a source of beneficial compounds with the potential for promoting health is considered, particularly their impact on the microbiota, immune system, and gut milieu because all of these fields interact closely to affect host nutrition, prevent chronic inflammation, and provide resistance to some pathogens.

Integrated serum pharmacochemistry and network pharmacology analyses reveal the bioactive metabolites and potential functional mechanism of ground cherry (Physalis pruinosa L.) in treatment of type 2 diabetes mellitus in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Different Physalis plants have been widely employed in traditional medicine for management of diabetes mellitus. Previous studies with respect to the in vivo antidiabetic activity of Physalis plants illustrated that they improved glucose and lipid metabolism in streptozotocin (STZ) -induced diabetic rats yet the mechanism of action of bioactive constituents of the different organs of Physalis plants on diabetes remains obscure.

AIM OF STUDY

Our objective is to study the effects of the different organs of ground cherry (P. pruinosa) on diabetes in rat models and elucidate their mechanism of actions through serum pharmacochemistry combined to network pharmacology analyses and in-vivo testing.

MATERIALS AND METHODS

Characterization of the constituents in the drug-dosed serum samples relative to the blank serum after treatment with different extracts was performed by UPLC -MS/MS technique. The absorbed metabolites where then subjected to network pharmacology analysis to construct an interaction network linking "compound-target-pathway". In vivo verification was implemented to determine a hypothesized mechanism of action on a STZ and high fat diet induced type II diabetes mellitus (T2DM) model based on functional and enrichment analyses of the Kyoto Encyclopedia of Genes and Genome and Gene Ontology.

RESULTS

Identification of a total of 73 compounds (22 prototypes and 51 metabolites) derived from P. pruinosa extracts was achieved through comparison of the serum samples collected from diabetic control group and extracts treated groups. The identified compounds were found to belong to different classes according to their structural type including withanolides, physalins and flavonoids. The absorbed compounds in the analyzed serum samples were considered as the potential bioactive components. The component-target network was found to have 23 nodes with 17 target genes including MAPK8, CYP1A1 and CYP1B1. Quercetin and withaferin A were found to possess the highest combined score in the C-T network. Integrated serum pharmacochemistry and network pharmacology analyses revealed the enrichment of leaves extract with the active constituents, which can be utilized in T2DM treatment. In the top KEGG pathways, lipid and atherosclerosis metabolic pathways in addition to T2DM pathways were found to be highly prioritized. The diabetic rats, which received leaves extract exhibited a substantial increment in GLUT2, INSR, IRS-1, PI₃K-p85 and AKT-ser473 proteins by 105%, 142%, 109%, 81% and 73%, respectively relative to the untreated diabetic group. The immunoblotting performed for MAPK and ERK1/2 part of the inflammatory pathway studied in STZ induced diabetic rats revealed that leaves, calyces and stems extracts resulted in a substantial diminish in p38-MAPK, ERK 1/2, NF-κB, and TNF-α. Histopathological examination revealed that the hepatic histoarchitecture was substantially improved in the leaves, stems, and clayces-treated rats in comparison with untreated diabetic rats. Further, pancreatic injuries, which induced by STZ were dramatically altered by the treatment with P. pruinosa leaves, calyces and stems extracts. β-cells in diabetic rats received leaves extract disclosed moderate insulin immunostaining with a notable increase in the mean insulin area%.

CONCLUSIONS

The study in hand offers a comprehensive study to clarify the bioactive metabolites of the different organs of P. pruinosa. The basic pharmacological effects and underlying mechanism of actions in the management of STZ and high fat diet induced T2DM were specifically covered in this paper.

Quercetin derivatives: Drug design, development, and biological activities, a review

More studies are needed to develop new drugs for problems associated with drug resistance and unfavorable side effects. The natural flavonoid of quercetin revealed a wide range of biological activities by the modulation of various targets and signaling pathways. However, quercetin's low solubility and poor bioavailability have restricted its applicability; as a result, researchers have attempted to design and synthesize numerous novel quercetin derivatives using various methodologies in order to modify quercetin's constraints; the physico-chemical properties of quercetin's molecular scaffold make it appealing for drug development; low molecular mass and chemical groups are two of these characteristics. Therefore, the biological activities of quercetin derivatives, as well as the relationship between activity and chemical structure and their mechanism of action, were investigated. These quercetin-based molecules could be valuable in the creation and discovery of medications for a number of diseases.

Olive oil and wine as source of multi-target agents in the prevention of Alzheimer disease

Olive oil and wine are consumed daily worldwide and they constitute the fundamental pillars of the healthy Mediterranean diet. Polyphenolic compounds, naturally present in both olive oil and wine, are responsible for their beneficial properties. Current studies have shown the neuroprotective effects of polyphenols independently of their well-known antioxidant action. In this work, we have focused on reviewing the protective effect of polyphenols from extra virgin olive oil and wine in Alzheimer´s disease (AD), to emphasize that both food could be a possible therapeutic tool. Beneficial effects have been described in β-aggregation, neurofibrillary tangles, autophagy and mitochondrial function, as well as in cerebral insulin resistance. Furthermore, to date a harmful dose has not been described. Both preclinical and clinical works demonstrate that polyphenols act on neuropathological and cognitive disorders of AD, preventing or stopping the onset of this devastating disease. However, there are certain limitations in these studies, since it is very difficult to research diseases that lead to cognitive impairment. Although all the findings obtained are very encouraging, more studies should be carried out to use the polyphenols from olive oil and wine as therapeutic agents in the progression of AD. Therefore, more longitudinal studies in humans with a homogeneous cohort of patients are necessary to corroborate the efficacy of these nutraceuticals, as well as analyze which is the most appropriate dose for this purpose.

In Vitro Expanded Bioaccessibility of Quercetin-3-Rutinoside and Quercetin Aglycone from Buckwheat Biscuits Formulated from Flours Fermented by Lactic Acid Bacteria

The expanded bioaccessibility of rutin (Ru) and quercetin (Q) from buckwheat biscuits (BBs) formulated from liquid-state fermented flours by selected lactic acid bacteria (LAB) were determined after gastrointestinal digestion. Fermentation of buckwheat flours caused a LAB-dependent variation in Ru and Q content. BBs baked at 220 °C for 30 min showed lower content of Ru and Q, and no correlation was found between the content of these compounds in fermented flours and BBs. The expanded bioaccessibility of Ru from BBs was low when its content in the soluble and insoluble fractions remaining after digestion in vitro was taken into account. Contrary results were found for Q bioaccessibility which had an index greater than 1, indicating the high Q bioaccessibility from BBs. Since very low Q content was noted in the insoluble fraction remaining after BBs digestion, the high Q bioaccessibility was determined to be due to its concentration in the soluble fraction.

Phenolic Compounds from Five Ericaceae Species Leaves and Their Related Bioavailability and Health Benefits

Some species of the Ericaceae family have been intensively studied because of the beneficial health impact, known since ancient times, of their chemical components. Since most studies focus on the effects of fruit consumption, this review aims to highlight the phenolic components present in the leaves. For this purpose, five species from Ericaceae family (bilberry-Vaccinium myrtillus L., lingonberry-V. vitis-idaea L., bog bilberry-V. uliginosum L., blueberry-V. corymbosum L. and bearberry-Arctostapylos uva-ursi L.) were considered, four of which can be found in spontaneous flora. The chemical composition of the leaves revealed three major phenolic compounds: chlorogenic acid, quercetin and arbutin. The health promoting functions of these compounds, such as antioxidant and anti-inflammatory properties that could have preventive effects for cardiovascular disease, neurodegenerative disorders, cancer, and obesity, have been exemplified by both in vitro and in vivo studies in this review. Furthermore, the importance of bioaccessibility and bioavailability of the phenolic compounds have been summarized. The findings highlight the fact that leaves of some Ericaceae species deserve increased attention and should be studied more profoundly for their biological activities, especially those from spontaneous flora.

Molecular mechanisms underlying protective role of quercetin in attenuating Alzheimer's disease

Quercetin belongs to the flavonoids family, which is present in most of the plants including fruits, vegetables, green tea and even in red wine having antioxidant activities. It is available as a food supplement in the market and has physiological health effects. Quercetin has anti-inflammatory, anticancer and anti-prostate activities along with its beneficial effects on high cholesterol, kidney transplantation, asthma, diabetes, viral infections, pulmonary, schizophrenia and cardiovascular diseases. Quercetin possesses scavenging potential of hydroxyl radical (OH^-), hydrogen peroxide (H₂O₂), and superoxide anion (O₂^-). These reactive oxygen species (ROS) hampers lipid, protein, amino acids and deoxyribonucleic acid (DNA) processing leading to epigenetic alterations. Quercetin has the ability to combat these harmful effects. ROS plays a vital role in the progression of Alzheimer's disease (AD), and we propose that quercetin would be the best choice to overcome cellular and molecular signals in regulating normal physiological functions. However, data are not well documented regarding exact cellular mechanisms of quercetin. The neuroprotective effects of quercetin are mainly due to potential up- and/or down-regulation of cytokines via nuclear factor (erythroid-derived 2)-like 2 (Nrf2), Paraoxonase-2, c-Jun N-terminal kinase (JNK), Protein kinase C, Mitogen-activated protein kinase (MAPK) signalling cascades, and PI3K/Akt pathways. Therefore, the aim of the present review was to elaborate on the cellular and molecular mechanisms of the quercetin involved in the protection against AD.

Different antitumor effects of quercetin, quercetin-3′-sulfate and quercetin-3-glucuronide in human breast cancer MCF-7 cells

This study was designed to investigate the tumor-inhibitory effects of quercetin (Que) and its water-soluble metabolites, quercetin-3′-sulfate (Q3′S) and quercetin-3-glucuronide (Q3G), as well as to make the molecular mechanism and structure-antitumor relationship clear.

Chemoenzymatic Preparation and Biophysical Properties of Sulfated Quercetin Metabolites

Sulfated quercetin derivatives are important authentic standards for metabolic studies. Quercetin-3′-O-sulfate, quercetin-4′-O-sulfate, and quercetin-3-O-sulfate as well as quercetin-di-O-sulfate mixture (quercetin-7,3′-di-O-sulfate, quercetin-7,4′-di-O-sulfate, and quercetin-3′,4′-di-O-sulfate) were synthetized by arylsulfotransferase from Desulfitobacterium hafniense. Purified monosulfates and disulfates were fully characterized using MS and NMR and tested for their 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺) and N,N-dimethyl-p-phenylenediamine (DMPD) radical scavenging, Folin-Ciocalteau reduction (FCR), ferric reducing antioxidant power (FRAP), and anti-lipoperoxidant activities in rat liver microsomes damaged by tert-butylhydroperoxide. Although, as expected, the sulfated metabolites were usually less active than quercetin, they remained still effective antiradical and reducing agents. Quercetin-3′-O-sulfate was more efficient than quercetin-4′-O-sulfate in DPPH and FCR assays. In contrast, quercetin-4′-O-sulfate was the best ferric reductant and lipoperoxidation inhibitor. The capacity to scavenge ABTS^+• and DMPD was comparable for all substances, except for disulfates, which were the most efficient. Quantum calculations and molecular dynamics simulations on membrane models supported rationalization of free radical scavenging and lipid peroxidation inhibition. These results clearly showed that individual metabolites of food bioactives can markedly differ in their biological activity. Therefore, a systematic and thorough investigation of all bioavailable metabolites with respect to native compounds is needed when evaluating food health benefits.

An Integrated View of the Effects of Wine Polyphenols and Their Relevant Metabolites on Gut and Host Health

Over the last few decades, polyphenols, and flavonoids in particular, have attracted the interest of researchers, as they have been associated with the health-promoting effects derived from diets rich in vegetables and fruits, including moderate wine consumption. Recent scientific evidence suggests that wine polyphenols exert their effects through interactions with the gut microbiota, as they seem to modulate microbiota and, at the same time, are metabolized by intestinal bacteria into specific bioavailable metabolites. Microbial metabolites are better absorbed than their precursors and may be responsible for positive health activities in the digestive system (local effects) and, after being absorbed, in tissues and organs (systemic effects). Differences in gut microbiota composition and functionality among individuals can affect polyphenol activity and, therefore, their health effects. The aim of this review is to integrate the understanding of the metabolism and mechanisms of action of wine polyphenols at both local and systemic levels, underlining their impact on the gut microbiome and the inter-individual variability associated with polyphenols' metabolism and further physiological effects. The advent of promising dietary approaches linked to wine polyphenols beyond the gut microbiota community and metabolism are also discussed.

The phenolic profiles of Radix Tetrastigma after solid phase extraction (SPE) and their antitumor effects and antioxidant activities in H22 tumor-bearing mice

Photographic illustrations of phenolic profiles, antitumor effects and antioxidant activities of Radix Tetrastigma after solid phase extraction (SPE) in H22 tumor-bearing mice.

Detection of 191 Taxifolin Metabolites and Their Distribution in Rats Using HPLC-ESI-IT-TOF-MS(n)

Taxifolin is a ubiquitous bioactive constituent of foods and herbs. To thoroughly explore its metabolism in vivo, an HPLC-ESI-IT-TOF-MSⁿ method combined with specific metabolite detection strategy was used to detect and identify the metabolites of taxifolin in rats. Of the 191 metabolites tentatively identified, 154 were new metabolites, 69 were new compounds and 32 were dimers. This is the first report of the in vivo biotransformation of a single compound into more than 100 metabolites. Furthermore, acetylamination and pyroglutamic acid conjugation were identified as new metabolic reactions. Seventeen metabolites were found to have various taxifolin-related bioactivities. The potential targets of taxifolin and 63 metabolites were predicted using PharmMapper, with results showing that more than 60 metabolites have the same five targets. Metabolites with the same fragment pattern may have the same pharmacophore. Thus these metabolites may exert the same pharmacological effects as taxifolin through an additive effect on the same drug targets. This observation indicates that taxifolin is bioactive not only in the parent form, but also through its metabolites. These findings enhance understanding of the metabolism and effective forms of taxifolin and may provide further insight of the beneficial effects of taxifolin and its derivatives.

Potential of Excipient Emulsions for Improving Quercetin Bioaccessibility and Antioxidant Activity: An in Vitro Study

The potential for excipient emulsions to enhance the bioaccessibility and antioxidant activity of quercetin was determined in this study. Oil-in-water excipient emulsions containing two levels (4 or 10%) of small lipid droplets (d < 250 nm) were prepared from a long-chain triglyceride (corn oil). The solubilization of quercetin by the excipient emulsions was faster than by bulk corn oil or bulk water, and the solubilization rate was higher at 100 °C than at 30 °C. The bioaccessibility of quercetin samples was determined using an in vitro gastrointestinal model, and the bioactivity of quercetin was determined using a rat feeding study. The excipient emulsions were more effective at enhancing quercetin bioaccessibility and rat plasma antioxidant activity than either bulk oil or bulk water. This effect was attributed to the rapid digestion of the long chain triglycerides when they were in an emulsified form, which led to the rapid production of mixed micelles capable of solubilizing, protecting, and transporting quercetin.

Effect of the Fructus Ligustri Lucidi extract and its monomers quercetin and oleanolic acid on the adhesion and migration of melanocytes and intracellular actin

The present study aimed to investigate the effects of the Fructus Ligustri Lucidi (FLL) extract and its monomers quercetin and oleanolic acid on the adhesion and migration of human epidermal melanocytes (MCs) and intracellular actin. The human epidermal MCs were cultured and identified. The cells were treated with different concentrations of FLL extract, quercetin and oleanolic acid. The adhesion and migration abilities of the cells were determined by the fibronectin-coated culture experiment and Transwell assay, respectively. The structure and distribution of intracellular actin were observed by confocal laser microscopy, with semi-quantitative analysis. Results showed that compared with the control group, 0.0375-0.3 mg/ml of the FLL extract and 40 µM quercetin significantly improved the adhesion rate of MCs (P<0.05). The numbers of MCs permeating the microporous membrane in the 0.15 mg/ml FLL extract and 12 µM oleanolic acid groups were 43.7 and 30.3, respectively, significantly higher compared to the control group (P<0.01). In the control group, the intracellular actin was less, and the stress fiber structure was not clear. In the 0.15 mg/ml FLL extract, 12 µM oleanolic acid and 40 µM quercetin groups, there were numerous bunched stress fibers, indicating the aggregation of filamentous fibrous actin. The mean optical densities of actin expression in the 0.15 mg/ml FLL extract, 12 µM oleanolic acid and 40 µM quercetin groups were significantly higher compared to the control group (P<0.05). The FLL extract has a significant stimulatory effect on the adhesion and migration of human epidermal MCs. The mechanism may be associated with the promotion of intracellular actin cytoskeleton aggregation.

Quercetin and isorhamnetin aglycones are the main metabolites of dietary quercetin in cerebrospinal fluid

SCOPE

Reports on the protective effect of certain foods on brain functions are numerous; however, the permeability of the brain barriers by food components is still hardly recognised. There have been in vitro studies aimed at demonstrating this possibility, but not much is known about this phenomenon in in vivo systems. The objective of the study was to determine the metabolites of dietary quercetin (Q) in urine, blood plasma and cerebrospinal fluid (CSF) after intra-rumen administration of Q rich onion dry skin in an animal model.

METHODS AND RESULTS

Eleven sheep had permanently implanted cannulas in the third ventricle of the brain as the means for CSF collection. The animals were administered Q at the dose of 10 mg/kg bwt. For 12 h the concentration of Q metabolites was measured in urine, blood plasma, and CSF. It was demonstrated that while in blood plasma Q and isorhamnetin mono-glucuronides or mono-sulphates were the main metabolites (80%), in CSF their aglycones were the dominating ones (88%).

CONCLUSION

Q and IR aglycones are the main Q metabolites present in CSF after dietary Q intake. Their passive transport through blood-CSF barrier or a de-conjugating mechanism within that barrier may be involved.